1. Field of the Invention
This invention relates to an agent for external application, particularly agent to be applied to the skin having excellent skin lightening and whitening effect for face care and body care and use thereof.
2. Description of the Prior Art
Cosmetics having a skin lightening and whitening effect are of very great interest to consumers, and there have hitherto been used as effective components peroxides such as hydrogen peroxide, zinc peroxide and magnesium peroxide, ascorbic acid, glutathione, colloidal sulfur, and various natural substances. However, hydrogen peroxide and ascorbic acid have problems regarding stability, preservability, etc., and moreover it is hard to say that their effects are adequate. Further, glutathione and colloidal sulfur have a peculiar smell, which causes a problem when it is added to cosmetic composition.
Further, hydroquinone is used as a skin-decoloring agent in U.S.A., etc., but it has a problem in view of safety (irritating property and allergic property) when compounded into cosmetics.
Therefore, there have been developed various cosmetics which do not have the above problems and can produce a skin lightening and whitening effect on the skin. There have been developed, for example, agents for external application using kojic acid and kojic acid derivatives [Japanese Patent Publication for Opposition Purpose (hereinafter referred to as "J. P. KOKOKU") No. 56-18569, Japanese Patent Unexamined Published Application (hereinafter referred to as "J. P. KOKAI") No. 53-3538, and J. P. KOKOKU Nos. 61-60801, 58-22151 and 60-9722], cosmetics containing quercetin as an effective component (J. P. KOKAI No. 55-92305), cosmetics containing fatty acid esters of quercetin as effective components (J. P. KOKAI No. 58-131911), cosmetics containing catechin, etc. as effective components (J. P. KOKAI No. 52-44375), etc. However, in practical use, these entail various problems such that the stability of the fresh components is inadequate, because their effects are not adequately exhibited in animals and human beings even though their effects at the cell level are noticeable.